I assume he is seeing a doctor since he has had blood work done. I would tell your brother to abstain from alcohol, pain meds (tylenol), supplements, etc for one month and re-test blood including another Hepatitis panal. If liver enzymes are still elevated make appointment with a liver specialist (Hepatologist). best of luck
Al alt level of 81 is elevated, but not terribly. If you are sure he is neg for hep a,b and c,
the problem could be excess alcohol consumption or fatty liver. Really, he needs to
see a doctor. That would be his best choice.